Insulated gate bipolar transistor (IGBT) electrostatic discharge (ESD) protection devices

ABSTRACT

Insulated gate bipolar transistor (IGBT) electrostatic discharge (ESD) protection devices are presented. An IGBT-ESD device includes a semiconductor substrate and patterned insulation regions disposed on the semiconductor substrate defining a first active region and a second active region. A high-V N-well is formed in the first active region of the semiconductor substrate. A P-body doped region is formed in the second active region of the semiconductor substrate, wherein the high-V N-well and the P-body doped region are separated with a predetermined distance exposing the semiconductor substrate. A P +  doped drain region is disposed in the high-V N-well. A P +  diffused region and an N +  doped source region are disposed in the P-body doped region. A gate structure is disposed on the semiconductor substrate with one end adjacent to the N +  doped source region and the other end extending over the insulation region.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to electrostatic discharge (ESD) protection devices, and in particular, to insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection devices.

2. Description of the Related Art

Conventional high voltage electrostatic discharge (ESD) protection devices include lateral diffused metal oxide semiconductor (LDMOS) power transistors, metal oxide semiconductor field effect transistors (MOSFET), silicon control rectifiers (SCR), bipolar junction transistors (BJT), diodes and field oxide devices (FOD). For a device experiencing high voltage electrostatic discharge (ESD), an inner circuit may either be damaged or result in a latch-up effect due to an overly high trigger voltage and an overly low holding voltage. Therefore, by adding an additional driving circuit to the device, or by regulating layout parameters, trigger voltage can be reduced such that a holding voltage of the device can be higher than an operation voltage. Thus, resulting in high voltage electrostatic discharge (ESD) protection.

For conventional ultra-HV devices, a silicon-on-insulator (SOT) substrate and fabrication processes thereof are adopted to isolate individual devices, thereby eliminating parasitic effects between devices during high voltage operation. However, by using the silicon-on-insulator (SOT) substrate and fabrication processes thereof, heat dissipation ability of the ultra-HV devices may be diminished. Thus, an effective solution for dissipating heat generated by ESD protection devices has long been pursued. Meanwhile, during fabrication of high-voltage devices, the diffused concentration of well doped regions is quite low, such that relative impedance increases, therefore, diminishing the ability for the ESD protection devices to be uniformly turned on.

BRIEF SUMMARY OF THE INVENTION

Accordingly, in order to overcome the problems mentioned previously and to achieve using an insulated gate bipolar transistor (IGBT) device as an electrostatic discharge (ESD) protection device, the drain region layout of IGBT devices has been improved, such that ESD protection devices can be turned on more uniformly to improve ESD protection capability.

An embodiment of the invention provides an insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a semiconductor substrate; a patterned insulation region disposed on the semiconductor substrate defining a first active region and a second active region; a high-voltage N-well formed in the first active region of the semiconductor substrate; a P-body doped region formed in the second active region of the semiconductor substrate, wherein the high-voltage N-well and the P-body doped region are separated with a predetermined distance exposing the semiconductor substrate; a P⁺ doped drain region disposed in the high-voltage N-well; a P⁺ diffused region and an N⁺ doped source region disposed in the P-body doped region; and a gate structure disposed on the semiconductor substrate with one end adjacent to the N⁺ doped source region and with the other end extending over the patterned insulation region.

Another embodiment of the invention provides an insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a semiconductor substrate; a high-voltage N-well formed in the semiconductor substrate; a patterned insulation region disposed on the high-voltage N-well defining a first active region and a second active region; an N-type double diffused region disposed in the first active region of the high-voltage N-well; a P⁺ doped drain region disposed in the N-type double diffused region; a P-body doped region formed in the second active region of the high-voltage N-well, wherein the N-type double diffused region and the P-body doped region are separated with a predetermined distance exposing the high-voltage N-well; a pair of N⁺ and P⁺ doped source regions disposed in the P-body doped region; and a gate structure disposed on the high-voltage N-well with one end adjacent to the N⁺ doped source region and with the other end extending over the patterned insulation region.

Another embodiment of the invention provides an insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a semiconductor substrate; a high-voltage N-well formed in the semiconductor substrate; a patterned insulation region disposed on the high-voltage N-well defining a first active region and a second active region; a P-type double diffused region disposed in the first active region of the high-voltage N-well; a P⁺ doped drain region disposed in the P-type double diffused region; a P-body doped region formed in the second active region of the high-voltage N-well, wherein the P-type double diffused region and the P-body doped region are separated with a predetermined distance exposing the high-voltage N-well; a pair of N⁺ and P⁺ doped source regions disposed in the P-body doped region; and a gate structure disposed on the high-voltage N-well with one end adjacent to the N⁺ doped source region and with the other end extending over the patterned insulation region.

Another embodiment of the invention provides an insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a semiconductor substrate; a high-voltage P-well formed in the semiconductor substrate; a high-voltage N-well formed in the semiconductor substrate; patterned insulation regions disposed on the semiconductor substrate defining a first active region in the high-voltage N-well and a second and a third region in the high-voltage P-well; a P⁺ doped drain region disposed in first active region; an N⁺ doped source region disposed in the second active region and a P-body doped region disposed in the third active region; and a gate structure disposed on the high-voltage P-well with one end adjacent to the N⁺ doped source region and with the other end extending over the patterned insulation region.

Another embodiment of the invention provides an insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a semiconductor substrate; a patterned insulation region disposed on the semiconductor substrate defining a first active region and a second active region; a gate structure disposed on the first active region of the semiconductor substrate; an N-type double diffused region disposed on one side of the gate structure and formed in the first active region of the semiconductor substrate; an N-well formed in the N-type double diffused region extending towards the semiconductor substrate; a P⁺ doped drain region disposed in the N-well; an N⁺ doped source region disposed on the other side of the gate structure in the semiconductor substrate; and a P⁺ diffused region disposed in the second active region of the semiconductor substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1A is a cross section of an embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention;

FIG. 1B shows a plan view of the P⁺ doped drain region, the first active region, and the high-voltage N-well;

FIG. 2A is a cross section of another embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention;

FIG. 2B and FIG. 2C respectively show plan views of the P⁺ doped drain region, the first active region, and the high-voltage N-well;

FIG. 3A is a cross section of further another embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention;

FIG. 3B is a cross section of still another embodiment of the IDBT-ESD protection device of the invention;

FIG. 4A is a cross section of further another embodiment of the IDBT-ESD protection device of the invention;

FIG. 4B is a cross section of further another embodiment of the IDBT-ESD protection device of the invention; and

FIG. 5 is a cross section of further another embodiment of the IDBT-ESD protection device of the invention.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact or not in direct contact.

FIG. 1A is a cross section of an embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention. In FIG. 1A, an IDBT-ESD protection device 100 a includes a semiconductor substrate 110 and patterned insulation regions 130 a, 130 b and 130 c disposed on the semiconductor substrate 110 defining a first active region OD1 and a second active region OD2. According to an embodiment of the invention, the semiconductor substrate 110 includes a silicon-on-insulator (SOI) substrate, for example, a P-type silicon substrate 101 with an N-type buried layer 102 thereon. A P-type epitaxial layer 103 is formed on the N-type buried layer 102. An isolation region 105 separates the IGBT-ESD protection devices 100 a from other devices on the substrate 110.

A high-voltage N-well 115 is formed in the first active region OD1 of the semiconductor substrate 110. A P-body doped region 120 is formed in the second active region OD2 of the semiconductor substrate, wherein the high-voltage N-well 115 and the P-body doped region 120 are separated with a predetermined distance exposing the semiconductor substrate. A diffusion region 113 extends from the high-voltage N-well 115 to the P-body doped region 120. A P⁺ doped drain region 117 is disposed in the high-voltage N-well 115. Drain electrodes 145 a and 145 b electrically contact the P⁺ doped drain region 117. An N⁺ doped source region 124 and a P⁺ diffused region 122 are disposed in the P-body doped region 120. Source electrodes 135 a and 135 b, respectively contact the N⁺ doped source region 124 and the P⁺ diffused region 122. A gate structure 140 is disposed on the semiconductor substrate with one end adjacent to the N⁺ doped source region 124 and with the other end extending over the patterned insulation region 130 b.

According to an embodiment of the invention, the area of the P⁺ doped drain region 117 can be greater than the first active region OD1, but smaller than the high-voltage N-well 115. The plan view of the P⁺ doped drain region 117, the first active region OD1, and the high-voltage N-well 115 is shown in FIG. 1B.

FIG. 2A is a cross section of another embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention. In FIG. 2A, the IDBT-ESD protection device 100 b is nearly identical to the IDBT-ESD protection device 100 a of FIG. 1A and for simplicity, like descriptions are omitted. The embodiment of the IDBT-ESD protection device 100 b is different from the IDBT-ESD protection device 100 a in that the area of the P⁺ doped drain region 217 a is smaller than the area of the high-voltage N-well 115, wherein the layout plan view is shown in FIG. 2B. Within the high-voltage N-well 115, an extrinsic doped interface is interposed between the high-voltage N-well 115 and the P⁺ doped drain region 217 a to disperse and reduce about 0.7V of ESD voltage. According to another embodiment of the invention, the P⁺ doped drain region 217 b comprises a plurality of separated islands, wherein a plan view is shown in FIG. 2C. Since there are extrinsic doped interfaces between the islands 217 b and the high-voltage N-well 115, respectively, ESD voltage can be dispersed and reduced and the ESD protection device can be more uniformly turned on.

FIG. 3A is a cross section of further another embodiment of the insulated gate bipolar transistor electrostatic discharge (IDBT-ESD) protection device of the invention. In FIG. 3A, an IDBT-ESD protection device 300 a includes a semiconductor substrate 310 such as a P-type silicon substrate and a high-voltage N-well 115 is formed in the semiconductor substrate 310. Patterned insulation regions 130 a, 130 b and 130 c are disposed on the high-voltage N-well 115 defining a first active region OD1 and a second active region OD2. An N-type double diffused region 316 a is disposed in the first active region of the high-voltage N-well 315. A P⁺ doped drain region 317 is disposed in the N-type double diffused region 316 a. A P-body doped region 320 is formed in the second active region OD2 of the high-voltage N-well 315, wherein the N-type double diffused region 316 a and the P-body doped region 320 are separated with a predetermined distance exposing the high-voltage N-well 315. A pair of neighboring N⁺ doped source region 324 and P⁺ diffused region 322 is disposed in the P-body doped region 320. A gate structure 340 is disposed on the high-voltage N-well 315 with one end adjacent to the N⁺ doped source region 324 and with the other end extending over the patterned insulation region 330 b.

FIG. 3B is a cross section of still another embodiment of the IDBT-ESD protection device of the invention. In FIG. 3B, the IDBT-ESD protection device 300 b is nearly identical to the IDBT-ESD protection device 300 a of FIG. 3A and for simplicity, like descriptions are omitted. The embodiment of the IDBT-ESD protection device 300 b is different from the IDBT-ESD protection device 300 a in that a P-type double diffused region 316 b is disposed in the first active region of the high-voltage N-well 317. A P⁺ doped drain region 317 is disposed in the P-type double diffused region 316 b. Since both the P⁺ doped drain region 317 and the P-type double diffused region 316 b are P-type doped regions, the efficiency and performance of the ESD protection device can be further improved.

FIG. 4A is a cross section of further another embodiment of the IDBT-ESD protection device of the invention. In FIG. 4A, an IDBT-ESD protection device 400 a includes a semiconductor substrate 410. A high-voltage N-well 415 b is formed in the semiconductor substrate. A high-voltage P-well 415 c is formed in the semiconductor substrate. Patterned insulation regions 430 a-430 d are disposed on the semiconductor substrate defining a first active region in the high-voltage N-well 415 b and a second and a third region in the high-voltage P-well 415 c. A high voltage P-well 451 a is disposed underlying the isolation region 430 a. A P⁺ doped drain region 417 is disposed in the first active region. An N⁺ doped source region 424 is disposed in the second active region and a P-body doped region 422 is disposed in the third active region. A gate structure 440 is disposed on the high-voltage P-well 415 c with one end adjacent to the N⁺ doped source region 424 and with the other end extending over the patterned insulation region 430 b.

FIG. 4B is a cross section of further another embodiment of the IDBT-ESD protection device of the invention. In FIG. 4B, an IDBT-ESD protection device 400 b includes a semiconductor substrate 410. For example, the semiconductor substrate comprises a P-type silicon substrate 401 with a P-type epitaxial layer 403 thereon and an N-type buried layer 402 interposed between the P-type silicon substrate 401 and the P-type epitaxial layer 403. A high-voltage N-well 415 b is formed in the semiconductor substrate. A high-voltage P-well 415 c is formed in the semiconductor substrate. Patterned insulation regions 430 a-430 f are disposed on the semiconductor substrate defining a first active region in the high-voltage N-well 415 b and a second and a third region in the high-voltage P-well 415 c. A high voltage N-well 415 d is disposed underlying the isolation region 430 e. A P⁺ doped drain region 417 is disposed in the first active region. An N⁺ doped source region 424 is disposed in the second active region and a P-body doped region 422 is disposed in the third active region. Moreover, an additional P⁺ doped region 416 is disposed in the high-voltage P-well 415 a, and an additional P⁺ doped region 426 is disposed in the high-voltage P-well 415 e. A gate structure 440 is disposed on the high-voltage P-well 415 c with one end adjacent to the N⁺ doped source region 424 and with the other end extending over the patterned insulation region 430 c.

FIG. 5 is a cross section of further another embodiment of the IDBT-ESD protection device of the invention. In FIG. 5, an IDBT-ESD protection device 500 includes a semiconductor substrate 510 and patterned insulation regions 530 a-530 c disposed on the semiconductor substrate 510 defining a first active region and a second active region. A gate structure 540 is disposed on the first active region of the semiconductor substrate. An N-type double diffused region 516 is disposed on one side of the gate structure 540 and formed in the first active region of the semiconductor substrate 510. An N-well 515 is formed in the N-type double diffused region 516 extending towards the semiconductor substrate 510. A P⁺ doped drain region 517 is disposed in the N-well 515. An N⁺ doped source region 524 is disposed on the other side of the gate structure 540 in the semiconductor substrate. An N-type light doped drain (NLDD) region 524′ extends as underlying spacers of the gate structure 540. A P⁺ diffused region 522 is disposed in the second active region of the semiconductor substrate.

Note that the IDBT-ESD protection devices of each embodiment of the invention adopt a P⁺ doped drain region that is smaller than the high-voltage N-well such that an extrinsic doped interface is interposed between the high-voltage N-well and the doped drain region to disperse and reduce about 0.7V ESD voltage. Moreover, the P⁺ doped drain region can be divided into several separated islands in the high-voltage N-well. Since there are extrinsic doped interfaces between the islands and the high-voltage N-well, respectively, ESD voltage can be dispersed and reduced and the ESD protection device can be more uniformly turned on.

While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

1. An insulated gate bipolar transistor electrostatic discharge (IGBT-ESD) protection device, comprising: a P-type semiconductor substrate; a patterned insulation region disposed on the P-type semiconductor substrate defining a first active region and a second active region; a high-voltage N-well formed in the first active region of the P-type semiconductor substrate; a P-body doped region formed in the second active region of the P-type semiconductor substrate, wherein the high-voltage N-well and the P-body doped region are separated with a predetermined distance exposing the P-type semiconductor substrate; a P⁺ doped drain region disposed in the high-voltage N-well; a P⁺ diffused region and an N⁺ doped source region disposed in the P-body doped region; a gate structure disposed on the P-type semiconductor substrate with one end adjacent to the N⁺ doped source region and with the other end extending over the patterned insulation region; and a diffusion region extending from the high-voltage N-well to the P-body doped region, wherein the diffusion region and the P-body doped region are separated from each other only by a portion of the P-type semiconductor substrate free from any additionally doped region, and wherein a bottom of the diffusion region is aligned with that of the high-voltage N-well.
 2. The IGBT-ESD protection device as claimed in claim 1, wherein the area of the P⁺ doped drain region is smaller than the area of the first active region.
 3. The IGBT-ESD protection device as claimed in claim 2, wherein the P⁺ doped drain region comprises a plurality of separated islands.
 4. The IGBT-ESD protection device as claimed in claim 1, wherein the P-type semiconductor substrate comprises a silicon-on-insulator (SOI) substrate.
 5. The IGBT-ESD protection device as claimed in claim 1, wherein the portion of the P-type semiconductor substrate has a first boundary to the diffusion region and a second boundary to the P-body doped region, wherein the first and second boundaries are both directly under the gate structure and laterally between the second active region and the patterned insulation region. 